function sys=plants(t,x,dt)
sys=zeros(3,1);

lamb=1.2;
kd=0.08;
alpha=0.001;
PHI=0.01;

s=x(1);ds=x(2);gama=x(3);

sys(1)=ds;
sys(2)=-lamb*s-gama*saturate(ds/PHI,-1,1)-kd*dt;
sys(3)=1/alpha*abs(ds);

end